System and method for a compressor

ABSTRACT

Systems and methods of the invention relate to removing fluid from a compressor to mitigate condensation accumulated for a compressor. A controller can be configured to actuate a drain valve coupled to an aftercooler of a compressor and actuate a check valve to isolate air pressure of the aftercooler from a reservoir of the compressor. Through control of the drain valve of the aftercooler and the check valve, the controller removes fluid from the aftercooler to facitliate thermal management of a compressor.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application Ser. No. 61/636,192, filed Apr. 20, 2012, and entitled “SYSTEM AND METHOD FOR A COMPRESSOR.” The entirety of the aforementioned application is incorporated herein by reference.

BACKGROUND 1. Technical Field

Embodiments of the subject matter disclosed herein relate to air compressors.

2. Discussion of Art

Compressors compress gas, such as air. An air compressor can include three cylinders with two stages, and may be air cooled and driven by an electric motor. For example, the compressor can have two low pressure cylinders which deliver an intermediate pressure air supply to a single high pressure cylinder for further compression for final delivery to an air reservoir. Compressor and compressor components are subject to various failure modes, which increase difficulties in maintaining a healthy compressor.

It may be desirable to have a system and method that differs from those systems and methods that are currently available.

BRIEF DESCRIPTION

In an embodiment, a system is provided that includes a compressor operatively connectable to an engine, wherein the compressor includes a reservoir configured to store compressed air, an aftercooler that is configured to change a temperature of air that is delivered to the reservoir via an air line, and a first drain valve coupled to the aftercooler. The system further includes a check valve in line between the aftercooler and at least one of the air line or the reservoir, wherein the check valve is configured to isolate air pressure within the aftercooler and air pressure within the at least one of the air line or the reservoir. The system further includes a controller that is configured to actuate the check valve to isolate air pressure within the aftercooler and air pressure within the at least one of the air line or the reservoir, and to actuate the first drain valve coupled to the aftercooler to enable removal of fluid accumulated within the aftercooler. (For example, the check valve may first be actuated to isolate air pressure within the aftercooler and air pressure within the at least one of the air line or the reservoir, and then while the check valve is actuated and the air pressure isolated, the first drain valve may be actuated to enable removal of the fluid.)

In an embodiment, a method is provided (e.g., a method for controlling and/or operating a compressor) that includes at least the steps of: reducing a temperature of air that is delivered to a reservoir in the compressor; isolating air pressure within an aftercooler of the compressor from air pressure within at least one of an air line or the reservoir; and removing a portion of fluid from the aftercooler while maintaining air pressure in the at least one of the air line or the reservoir.

In an embodiment, a system for a compressor is provided and includes means for delivering air under pressure to a reservoir, means for changing a temperature of the air that is delivered to the reservoir, means for isolating air pressure within the temperature changing means from air pressure within the reservoir, and means for removing a portion of fluid from the temperature changing means while maintaining air pressure in the reservoir.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference is made to the accompanying drawings in which particular embodiments and further benefits of the invention are illustrated as described in more detail in the description below, in which:

FIG. 1 is an illustration of an embodiment of a vehicle system with a compressor;

FIG. 2 is an illustration of an embodiment of system that includes a compressor;

FIG. 3 is an illustration of an embodiment of a compressor;

FIGS. 4A-4D are illustrations of views of a check valve for a compressor;

FIGS. 5A-5B are illustrations of views of a check valve for a compressor;

FIG. 6 is an illustration of a system with a discharge line for a compressor;

FIG. 7 is an illustration of a system with a drain valve for an aftercooler of a compressor;

FIGS. 8A-8B are illustrations of views of an external oil filter utilized with a compressor;

FIGS. 9A-9B are illustrations of a view of an oil filter and a manifold for a compressor;

FIG. 10 is an illustration of a view of a manifold used to couple an oil filter to a compressor;

FIGS. 11A-11B are illustrations of views for an exhaust pipe for a high pressure cylinder to an aftercooler of a compressor;

FIG. 12 is an illustration of a view of an exhaust pipe for a compressor;

FIG. 13 is an illustration of a view of an exhaust pipe for a compressor;

FIG. 14 is an illustration of a view of an intercooler for a compressor;

FIG. 15 is an illustration of a view of an intercooler for a compressor;

FIG. 16 is an illustration of a view of a crankshaft interface for a thermal clutch of a compressor;

FIG. 17 is an illustration of a view of a thermal clutch and crankshaft interface for a compressor;

FIG. 18 is an illustration of a view of a thermal clutch for a compressor; and

FIG. 19 is a flow chart of an embodiment of a method for removing fluid from an aftercooler while maintaining pressure in a reservoir of a compressor.

DETAILED DESCRIPTION

Embodiments of the subject matter disclosed herein relate to systems and methods that facilitate removing fluid from a compressor to mitigate condensation accumulated in the compressor. A controller can be configured to actuate a drain valve coupled to an aftercooler of the compressor and to actuate a check valve to isolate air pressure of the aftercooler from a reservoir of the compressor. Through control of the drain valve of the aftercooler and the check valve, the controller removes fluid from the aftercooler to facitliate thermal management of the compressor. Moreover, a detection component can be configured to monitor at least one of a flow of air from an aftercooler drain valve, a flow from a drain valve, a flow from a discharge line, a flow from an exhaust port of a high pressure cylinder, among others. Based upon the detection component, the controller can further be configured to determine the presence of a high pressure cylinder discharge valve leak, based upon a flow from at least one of the check valve or the drain valve to the atmosphere. In an embodiment, the controller can be further configured communicate an alert related to the detected condition (e.g., discharge leak valve, exhaust port leak, among others). The alert can be a signal (e.g., diagnostic code, audio, text, visual, haptic, among others) that indicates a change in the monitored pressure of the intermediate stage of the compressor. This alert can be utilized to provide maintenance on the compressor or a portion thereof In an embodiment, the controller can be configured to schedule a maintenance operation based upon the detected condition and/or the communicated alert in order to perform preventative maintenance.

With reference to the drawings, like reference numerals designate identical or corresponding parts throughout the several views. However, the inclusion of like elements in different views does not mean a given embodiment necessarily includes such elements or that all embodiments of the invention include such elements.

The term “component” as used herein can be defined as a portion of hardware, a portion of software, or a combination thereof A portion of hardware can include at least a processor and a portion of memory, wherein the memory includes an instruction to execute. The term “vehicle” as used herein can be defined as any asset that is a mobile machine that transports at least one of a person, people, or a cargo, or that is configured to be portable from one location to another. For instance, a vehicle can be, but is not limited to being, a locomotive or other rail vehicle, an intermodal container, a marine vessel, a mining equipment, a stationary portable power generation equipment, an industrial equipment, a construction equipment, and the like. The term “loaded” as used herein can be defined as a compressor system mode where air is being compressed into the reservoir. The term “loaded start” as used herein can be defined as a compressor system mode in a loaded condition during a starting phase of the compressor. The term “unloaded” as used herein can be defined as a compressor system mode where air is not being compressed into the reservoir. The term “connector” or “coupling” can be a mechanism or device to join one or more pipes or tubes and is to include a cock-type connector or mechanism.

A compressor compresses gas, such as air. In some embodiments, the compressed gas is supplied to operate pneumatic or other equipment powered by compressed gas. A compressor may be used for mobile applications, such as vehicles. By way of example, vehicles utilizing compressors include locomotives, on-highway vehicles, off-highway vehicles, mining equipment, and marine vessels. In other embodiments, a compressor may be used for stationary applications, such as in manufacturing or industrial applications requiring compressed air for pneumatic equipment among other uses. The compressor depicted in the below figures is one which utilizes spring return inlet and discharge valves for each cylinder, wherein the movement of these valves is caused by the differential pressure across each cylinder as opposed to a mechanical coupling to the compressor crank shaft. The subject invention can be applicable to machines with either type of valve (e.g., spring return valves, mechanical coupled valves, among others) and the spring return valve is depicted solely for example and not to be limiting on the subject innovation.

The components of a compressor may degrade over time, resulting in performance reductions and/or eventual failure of the compressor. In vehicle applications, for example, a compressor failure may produce a road failure resulting in substantial costs to the vehicle owner or operator. In this context, a road failure includes a vehicle, such as a locomotive, becoming inoperative when deployed in service as a result of the failure or degradation of a compressor system that prevents operation or requires shutting down the vehicle until repairs can be made. Prior to a total failure, the detection of degraded components or other deterioration of the compressor may be used to identify incipient faults or other conditions indicative of deterioration. In response to detecting such conditions, remedial action may be taken to mitigate the risk of compressor failure and associated costs.

The systems and methods presently disclosed can also be used to diagnose and/or prognoses problems in a compressor prior to total compressor failure. If deterioration or degradation of the compressor is detected in the system, action can be taken to reduce progression of the problem and/or further identify the developing problem. In this manner, customers realize a cost savings by prognosing compressor problems in initial stages to reduce the damage to compressor components and avoid compressor failure and unplanned shutdowns. Moreover, secondary damage to other compressor components (e.g., pistons, valves, liners, and the like) or damage to equipment that relies upon the availability of the compressed gas from the compressor may be avoided if compressor problems are detected and addressed at an early stage.

FIG. 1 illustrates a block diagram of an embodiment of a vehicle system 100. The vehicle system 100 is depicted as a rail vehicle 106 (e.g., a locomotive) configured to run on a rail 102 via a plurality of wheels 108. The rail vehicle includes a compressor system with a compressor 110. In an embodiment, the compressor is a reciprocating compressor that delivers air at high pressure. In another embodiment, the compressor is a reciprocating compressor with a bi-directional drive system that drives a piston in a forward direction and the reverse direction. In an embodiment, the compressor receives air from an ambient air intake 114. The air is then compressed to a pressure greater than the ambient pressure and the compressed air is stored in reservoir 180, which is monitored by a reservoir pressure sensor 185. In one embodiment, the compressor is a two-stage compressor (such as illustrated in FIG. 2) in which ambient air is compressed in a first stage to a first pressure level and delivered to a second stage, which further compresses the air to a second pressure level that is higher than the first pressure level. The compressed air at the second pressure level is stored in a reservoir. The compressed air may then be provided to one or more pneumatic devices as needed. In other embodiments, the compressor 110 may be a single stage or multi-stage compressor.

The compressor includes a crankcase 160. The crankcase is an enclosure for a crankshaft (not shown in FIG. 1) connected to cylinders (not shown in FIG. 1) of the compressor. A motor 104 is employed to rotate the crankshaft to drive the pistons within the cylinders. In embodiments, the motor 104 may be an electric motor. In another embodiment, the crankshaft may be coupled to a drive shaft of an engine or other power source configured to rotate the crankshaft of the compressor. In each embodiment, the crankshaft may be lubricated with compressor oil that is pumped by an oil pump (not shown) and sprayed onto the crankshaft. The crankshaft is mechanically coupled to a plurality of pistons via respective connecting rods. The pistons are drawn and pushed within their respective cylinders as the crankshaft is rotated to compress a gas in one or more stages.

The rail vehicle further includes a controller 130 for controlling various components related to the vehicle system. In an embodiment, the controller is a computerized control system with a processor 132 and a memory 134. The memory may be computer readable storage media, and may include volatile and/or non-volatile memory storage. In an embodiment, the controller includes multiple control units and the control system may be distributed among each of the control units. In yet another embodiment, a plurality of controllers may cooperate as a single controller interfacing with multiple compressors distributed across a plurality of vehicles. Among other features, the controller may include instructions for enabling on-board monitoring and control of vehicle operation. Stationary applications may also include a controller for managing the operation of one or more compressors and related equipment or machinery.

In an embodiment, the controller receives signals from one or more sensors 150 to monitor operating parameters and operating conditions, and correspondingly adjust actuators 152 to control operation of the rail vehicle and the compressor. In various embodiments, the controller receives signals from one or more sensors corresponding to compressor speed, compressor load, boost pressure, exhaust pressure, ambient pressure, exhaust temperature, or other parameters relating to the operation of the compressor or surrounding system. In another embodiment, the controller receives a signal from a crankcase pressure sensor 170 that corresponds to the pressure within the crankcase. In yet another embodiment, the controller receives a signal from a crankshaft position sensor 172 that indicates a position of the crankshaft. The position of the crankshaft may be identified by the angular displacement of the crankshaft relative to a known location such that the controller is able to determine the position of each piston within its respective cylinder based upon the position of the crankshaft. In some embodiments, the controller controls the vehicle system by sending commands to various components. On a locomotive, for example, such components may include traction motors, alternators, cylinder valves, and throttle controls among others. The controller may be connected to the sensors and actuators through wires that may be bundled together into one or more wiring harnesses to reduce space in vehicle system devoted to wiring and to protect the signal wires from abrasion and vibration. In other embodiments, the controller communicates over a wired or wireless network that may allow for the addition of components without dedicated wiring.

The controller may include onboard electronic diagnostics for recording operational characteristics of the compressor. Operational characteristics may include measurements from sensors associated with the compressor or other components of the system. Such operational characteristics may be stored in a database in memory. In one embodiment, current operational characteristics may be compared to past operational characteristics to determine trends of compressor performance.

The controller may include onboard electronic diagnostics for identifying and recording potential degradation and failures of components of vehicle system. For example, when a potentially degraded component is identified, a diagnostic code may be stored in memory. In one embodiment, a unique diagnostic code may correspond to each type of degradation that may be identified by the controller. For example, a first diagnostic code may indicate a malfunctioning exhaust valve of a cylinder, a second diagnostic code may indicate a malfunctioning intake valve of a cylinder, a third diagnostic code may indicate deterioration of a piston or cylinder resulting in a blow-by condition. Additional diagnostic codes may be defined to indicate other deteriorations or failure modes. In yet other embodiments, diagnostic codes may be generated dynamically to provide information about a detected problem that does not correspond to a predetermined diagnostic code. In some embodiments, the controller modifies the output of charged air from the compressor, such as by reducing the duty cycle of the compressor, based on parameters such as the condition or availability of other compressor systems (such as on adjacent locomotive engines), environmental conditions, and overall pneumatic supply demand.

The controller may be further linked to display 140, such as a diagnostic interface display, providing a user interface to the operating crew and/or a maintenance crew. The controller may control the compressor, in response to operator input via user input controls 142, by sending a command to correspondingly adjust various compressor actuators. Non-limiting examples of user input controls may include a throttle control, a braking control, a keyboard, and a power switch. Further, operational characteristics of the compressor, such as diagnostic codes corresponding to degraded components, may be reported via display to the operator and/or the maintenance crew.

The vehicle system may include a communications system 144 linked to the controller. In one embodiment, communications system may include a radio and an antenna for transmitting and receiving voice and data messages. For example, data communications may be between vehicle system and a control center of a railroad, another locomotive, a satellite, and/or a wayside device, such as a railroad switch. For example, the controller may estimate geographic coordinates of a vehicle system using signals from a GPS receiver. As another example, the controller may transmit operational characteristics of the compressor to the control center via a message transmitted from communications system. In one embodiment, a message may be transmitted to the command center by communications system when a degraded component of the compressor is detected and the vehicle system may be scheduled for maintenance.

As discussed above, the term “loaded” refers to a compressor mode where air is being compressed into the reservoir. The compressor depicted is one which utilizes spring return inlet and discharge valves for each cylinder in which the movement of these valves is caused by the differential pressure across them as opposed to a mechanical coupling to the compressor crank shaft. The subject disclosure may be applicable to machines with either type of valve, but the spring return type will be illustrated here for the sake of brevity.

The controller can be configured to adjust at least one of the following: an actuation of a drain valve; an actuation of a check valve; an operation of the compressor; a scheduled maintenance for the compressor; a maintenance for the compressor; a service for the compressor; a diagnostic code of the compressor; an alert for the compressor; among others. In an embodiment, the controller can be configured to actuate a drain valve of an aftercooler for a compressor and a check valve that isolates the aftercooler from a reservoir of the compressor. In a more particular embodiment, the controller can be configured to identify a leak condition based upon a flow associated with a drain valve of the aftercooler. For instance, the controller can actuate the check valve to isolate pressure and actuate the drain valve of the aftercooler at the substantially same time to remove fluid from the aftercooler without losing pressure in the reservoir of the compressor. Moreover, the flow of the drain valve of the aftercooler and/or a discharge line (discussed in more detail below) can be monitored to determine a leak condition of a compressor or determine a potential leak condition of a compressor. In such case, an alert can be generated for the compressor.

The compressor 110 can include a detection component 128 that can be configured to detect at least one of a flow of a drain valve or a flow of a discharge line, wherein such detection is indicative of a leak condition for the compressor (discussed in more detail below). The detection component can be employed with the compressor to collect data that is indicative of a condition such as exhaust port leak, high pressure cylinder discharge valve leak, among others. In an embodiment, the controller can be configured to adjust the compressor based upon the detection component.

The detection component can be a stand-alone component (as depicted), incorporated into the controller component, or a combination thereof The controller component can be a stand-alone component (as depicted), incorporated into the detection component, or a combination thereof In another embodiment, the detection component can be a stand-alone component (as depicted), incorporated into the controller component, or a combination thereof

FIG. 2 illustrates a detailed view of the compressor set forth in FIG. 1 above. The compressor includes three cylinders 210, 220, 230. Each cylinder contains a piston 218, 228, 238 that is coupled to a crankshaft 250 via connecting rods 240, 242, 244. The crankshaft is driven by the motor to cyclically pull the respective pistons to a Bottom-Dead-Center (BDC) and push the pistons to a Top-Dead-Center (TDC) to output charged air, which is delivered to the reservoir via air lines 280, 282, 284, 286. In this embodiment, the compressor is divided into two stages: a low pressure stage and a high pressure stage to produce charged air in a stepwise approach. The low pressure stage compresses air to a first pressure level which is further compressed by the high pressure stage to a second pressure level. In this example, the low pressure stage includes cylinders 220, 230 and the high pressure stage includes cylinder 210.

In operation, air from the ambient air intake is first drawn into the low pressure cylinders via intake valves 222, 232, which open and close within intake ports 223, 233. The ambient air is drawn in as the low pressure cylinders are pulled towards BDC and the intake valves 222, 232 separate from intake ports 223, 233 to allow air to enter each cylinder 220, 230. Once the pistons reach BDC, the intake valves 222, 232 close the intake ports 223, 233 to contain air within each cylinder. Subsequently, pistons 228, 238 are pushed toward TDC, thereby compressing the ambient air initially drawn into the cylinders. Once the cylinders have compressed the ambient air to a first pressure level, exhaust valves 224, 234 within exhaust ports 225, 235 are opened to release the low pressure air into low pressure lines 280, 282.

The air compressed to a first pressure level is routed to an intermediate stage reservoir 260. The intermediate stage reservoir 260 received air from one stage of a multistage compressor and provides the compressed air to a subsequent stage of a multistage compressor. In an embodiment, the intermediate stage reservoir 260 is a tank or other volume connected between successive stages by air lines. In other embodiments, the air lines, such as low pressure lines 280, 282 provide sufficient volume to function as an intermediate stage reservoir without the need for a tank or other structure.

In an embodiment, the compressor system also includes an intercooler 264 that removes the heat of compression through a substantially constant pressure cooling process. One or more intercoolers may be provided along with one or more intercooler controllers 262. In some embodiments, the intercooler 264 is integrated with the intermediate stage reservoir 260. A decrease in the temperature of the compressed air increases the air density allowing a greater mass to be drawn into the high pressure stage increasing the efficiency of the compressor. The operation of the intercooler is controlled by the intercooler controller 262 to manage the cooling operation. In an embodiment, the intercooler controller 262 employs a thermostatic control through mechanical means such as via thermal expansion of metal. In a multistage compressor system having more than two stages, an intercooler may be provided at each intermediate stage.

The air at a first pressure level (e.g., low pressure air) is exhausted from the intercooler into low pressure air line 284 and subsequently drawn into the high pressure cylinder 210. More particularly, as piston 218 is pulled toward BDC, the intake valve 212 opens, thereby allowing the low pressure air to be drawn into the cylinder 210 via intake port 213. Once the piston 218 reaches BDC, the intake valve 212 closes to seal the low pressure air within the cylinder 210. The piston is then pushed upward thereby compressing the low pressure air into high pressure air. High pressure air is air at a second pressure level greater than the first pressure level, however the amount of compression will vary based upon the requirements of the application. As compression increases, the exhaust valve 214 is opened to allow the high pressure air to exhaust into high pressure line 286 via exhaust port 215. An aftercooler 270 cools the high pressure air to facilitate a greater density to be delivered to the reservoir via high pressure air line 288.

The above process is repeated cyclically as the crankshaft 250 rotates to provide high pressure air to the reservoir 180, which is monitored by the reservoir pressure sensor 185. Once the reservoir reaches a particular pressure level (e.g., 140 psi), the compressor operation is discontinued.

In some embodiments, the compressor includes one or more valves configured to vent compressed air from intermediate stages of the compressor system. The unloader valves and/or relief valves may be operated after compressor operations are discontinued, or may be operated during compressor operations to relieve pressure in the compressor system. In an embodiment, an unloader valve 268 is provided in the intermediate stage reservoir 260 and configured to vent the low pressure compressed air from the intermediate stage reservoir, low pressure air lines 280, 282 and intercooler 264. Venting compressed air reduces stress on system components during periods when the compressor is not in use and may extend the life of the system. In another embodiment, the unloader valve 268 operates as a relief valve to limit the buildup of pressure in the intermediate stage reservoir 260. In yet another embodiment, intake valves 222, 232 operate as unloader valves for the cylinders 220, 230 allowing compressed air in the cylinders to vent back to the ambient air intake 114. In another embodiment, the system 200 can include relief valves such as breather valve 174, a relieve valve on the intercooler 264 (shown in FIG. 4), a relieve valve for air line 286, a rapid unloader valve on the intercooler 264 (shown in FIG. 4)

A compressor, such as the compressor illustrated in FIG. 2, operates to charge the reservoir 180 with compressed air or other gas. Once the compressor charges the reservoir to a determined pressure value the compressor operation is discontinued. In some embodiments, when compressor operations are discontinued, one or more unloader valves are opened to vent intermediate stages of the compressor to the atmosphere. The intake valves of the cylinders as well as unloader valves of the intermediate stage reservoirs may all operate as unloader valves to vent the cylinders of the compressor to the atmosphere. Once the unloader valves are actuated and the cylinders and intermediate stages of the compressor have been vented to the atmosphere the pressure within the reservoir is expected to remain constant as previously discussed.

The compressor 110 can include additional features and/or components that are not illustrated in FIGS. 1 and 2. For instance, the system may include a Control Mag Valve (CMV), a Thermostatically Controlled Intercooler System (TCIS) bypass, a rapid unloader valve, an unloader valve for cylinder 230, an unloader valve for cylinder 220, a relief valve(s), among others.

The crankshaft can include a first end opposite a second end in which the first end is coupled to one or more connecting rods for each respective cylinder. The crankshaft, cylinders, and pistons are illustrated in BDC position based upon the location of the first end. BDC position is a location of the first end at approximately negative ninety degrees (−90 degrees) or 270 degrees. A TDC position is a location of the first end at approximately ninety degrees (90 degrees) or −270 degrees.

As discussed above, the controller can be configured to actuate a check valve 290 and a drain valve 292 of the aftercooler 270 to facilitate removing fluid from the compressor and in particular the aftercooler. In an embodiment, the drain valve can be coupled to a drain line 294 that can include a first end coupled the drain valve and a second end opposite the first end open to the atmosphere. In another embodiment, a discharge line (not shown) can tie into the drain line 294 for discharge into the atmosphere. In such embodiment, one or more additional lines or valves (e.g., drain valve for intercooler, actuator lines, among others) can be coupled to the discharge line for release to the atmosphere.

In an embodiment, the controller can actuate the check valve 290 and/or the drain valve 292 prior to a starting of the compressor. In another embodiment, the controller can actuate the check valve 290 and/or the drain valve 292 while the compressor is in an unloaded condition.

FIGS. 3-7 illustrate the check valve 290, the drain valve 292, and other components of the compressor. In a view 300 of FIG. 3, an actuation line 302 can interconnect one or more unloader valves of the compressor. (View 300 of FIG. 3 shows the compressor generally, which may be the compressor 110 of FIG. 2.) The view 300 illustrates the compressor with the high pressure cylinder 210 and at least one low pressure cylinder (e.g., low pressure cylinder 230, low pressure cylinder 220). The intercooler 264 can include a drain valve 296 that is connected to a discharge line 298. The discharge line 298 can open to the atmosphere to allow release of at least one of the actuation line 302, the drain valve 292 of the aftercooler 270, and/or the drain line 294. In an embodiment, the actuation line can connect to the drain line via one or more couplings or connectors. As depicted, the actuation line 302 can meet with the drain line 294 at the drain valve 296, which ties into the discharge line 298. In an embodiment, the routing of the actuation line 302 can be fitted to the cylinder style head and to minimize handling damage.

Turning to FIGS. 4A-4D, the check valve 290 is illustrated. In view 400 (FIG. 4A), an adapter plate 402 is illustrated. In an example, the adapter plate 402 can be hydro-formed. In view 404 (FIG. 4B), a gasket 406 can be used with the adapter plate 402. For instance, the gasket 406 can be an o-ring. View 408 (FIG. 4C) illustrates the check valve 290 and the adapter plate 402. View 412 (FIG. 4D) illustrates a gasket 414 with the check valve 290, wherein the gasket 414 can be a snap-ring for example. In an embodiment, the check valve 290 is an inlet discharge check valve that addresses leakage issues with cylinder heads and allows for the addition of the drain valve 292 by isolating the pressure in the aftercooler 270 from the pressure in the reservoir 180. Turning to FIGS. 5A and 5B, a view 500 depicts the check valve 292 within the aftercooler 270 affixed to the aftercooler with one or more screws 504. A view 502 illustrates the adapter plate 402 as well as the drain valve 292.

FIG. 6 illustrates a system 600 that includes the drain valve 296 for the intercooler 264. The drain valve 296 can be coupled to the discharge line 298 that opens to the atmosphere. In this embodiment, the discharge line 298 is a pipe that is directionally angled away from the compressor to avoid clogging the aftercooler 270. The drain valve 296 can further include connectors or couplings that tie in the actuation lines 302 and/or the drain line 294. In an embodiment, the discharge line 298 can be a non-conductive nylon tubing in which the opening to the atmosphere is away from the aftercooler and from a potential user. Continuing with illustrations of the lines, FIG. 7 depicts a system 700 that includes the drain line 294 connected to the drain valve 292 associated with the aftercooler 270. The drain valve 292 can be coupled to the drain line 294 via a connector or coupling. For instance, the coupling or connector can be an isolation cock. For example, the drain line 294 can include a connector 702 to couple to the drain valve 292 and/or a pipe that connects to the drain valve 292. A connector 704 can be an isolation cock connector that can be used for diagnostics. The isolation cock connector can be a discharge isolation cock. A mounting bracket 706 can further be included with the drain valve 292.

FIGS. 8A-10 relate to an oil filter for the compressor. In FIG. 8A, a view 800 illustrates an oil filter 802 and a manifold 804, wherein the oil filter is external to the compressor 110 (see FIGS. 1 and 2). The oil filter can be utilized to filter oil that is used with the motor 104 (see FIG. 1). A view 808 (FIG. 8B) illustrates lines associated with the oil filter 802 and at least one connection 806 at an oil pump. Turning to FIG. 9A, the oil filter 802 is illustrated in view 900. The oil filter 802 includes the manifold 804 (see also FIG. 9B) that allows attachment of the oil filter 802 for use with the compressor 110 and/or motor 104. The oil filter 802 can further include at least one of a gasket 902 (e.g., a square cut gasket), a connector (e.g., an adapter for oil in), a fastener 906 (e.g., ⅜-16 fastener), a relief valve 908 (e.g., an inline pressure relief valve), a port 910 (e.g., a plugged port that provides access to vent pin), an oil vent 912 (e.g., filter removal oil vent), a vent pin 914 (e.g., filter removal oil vent valve), or a pressure port 916 (e.g., post filter pressure port). FIG. 10 illustrates a view 1000 that depicts the vent pin 914 and a pre-filter port 1004, wherein the pre-filter port 1004 can be an external pre-filter port provided for external oil pump application(s). For example, the pre-filter port allows connectivity to access a source of the oil before the oil enters the filter. In another example, the pre-filter port allows a test device to connect. In another embodiment, the pre-filter port is an auxiliary access to the oil. In an embodiment, the oil can be drained from the oil filter 802 by creating a vent hole on a top portion (side that is not connected to the manifold 804) and activating the vent pin 914 to equalize pressure to enable flow of oil from the oil filter 802 into at least one of the motor, oil pump, among others.

FIGS. 11A-13 depict an exhaust pipe 1104 for the compressor 110. FIG. 11A illustrates a view 1100 of the compressor that includes the high pressure cylinder 210, the low pressure cylinder 230, the intercooler 264, and the aftercooler 270. The view 1100 further illustrates the exhaust pipe 1104 that connects the high pressure cylinder 210 to the aftercooler 270. A view 1102 (FIG. 11B) further illustrates a perspective of the exhaust pipe 1104 that connects the high pressure cylinder 210 to the aftercooler 270. The view 1102 also illustrates low pressure cylinder 220. The exhaust pipe 1104 is routed to minimize access to burn surfaces and to provide accessible location for an aftercooler pressure relief valve. The routing of the exhaust pipe 1104 facilitates a location for the aftercooler bypass. FIG. 12 illustrates a perspective view 1200 of the exhaust pipe 1104. The exhaust pipe 1104 can include one or more pre-formed elbows 1202, an inline pressure relief valve 1206 (e.g., as well as aftercooler by-pass), and tubing 1208 that bypasses and provides access for oil servicing. In an embodiment, the tubing 1208 can be ¾ inch (20 mm) tubing with fire sleeve protection, and the like. In an example, the exhaust pipe 1104 can include one or more bends 1204 and can be, for instance, 2 inch (50 mm) pipe. In an embodiment, the in-line pressure relief valve and aftercooler bypass 1206 can be located on a warm side to minimize freezing and eliminate continual bypass design. Turning to FIG. 13, a view 1300 illustrates an embodiment of the exhaust pipe 1104 which can include a heat shield 1302, a relief valve (e.g., aftercooler pressure relief valve in a position to eliminate removal while compressor is removed/installed), and a pressure port 1306. For instance, the pressure port 1306 can provide diagnostics including, but not limited to, discharge check valve (discussed above).

FIGS. 14 and 15 illustrate an intercooler for the compressor. FIG. 14 illustrates a view 1400 of the intercooler 264 that includes a high pressure cylinder connector 1402, a low pressure cylinder connector 1404, and a low pressure cylinder connector 1406. In an embodiment, the intercooler 264 is sized to meet requirements of motor-driven applications and/or load. In particular, the intercooler 264 can eliminate one or more cooler covers required by a dual cooler design. Turning to FIG. 15, a perspective view 1500 is provided of the intercooler 264. The view 1500 illustrates an embodiment of the intercooler 264 that includes a drain valve or drain port 1502 (e.g., drain port with a connector to accept the drain valve and eliminates the use of a heater), a pressure relief valve 1504 (e.g., an inter-stage pressure relief valve that provides improved access for servicing or repair), and/or a pressure connect port 1506 (e.g., pressure connect port provided for diagnostics).

FIGS. 16-18 relate to a thermal clutch and interface for the compressor and in particular the crankshaft of the compressor. FIG. 16 is a cross-sectional view of a crankshaft interface 1600 that can connect to the crankshaft 250 of the compressor. Turning to FIG. 17, a cross-sectional view 1700 illustrates the crankshaft 250, a fan blade 1706, a fan blade 1708, a thermal clutch 1702, and the crankshaft interface 1600. FIG. 18 illustrates a view 1800 of the thermal clutch 1702 with a clutch mechanism 1804. In an embodiment, the thermal clutch 1702 can engage the crankshaft 250 to activate a fan (e.g., to rotate one or more fan blades 1706, 1708 for the compressor, wherein the thermal clutch 1702 engages the crankshaft 250 based upon a temperature of an air flow discharged from the compressor. By utilizing the thermal clutch 1702 with the compressor, a Revolutions Per Minute (RPM) can be reduced and/or a Horse Power (HP) can be reduced. In an embodiment, the cooling fan can be run at a reduced rate when the compressor is cold (e.g., 20% synchronous speed, for instance) and a higher rate when the compressor is hot (e.g., 90% synchronous speed, for instance). One or more clutch ducts on the thermal clutch 1702 allows the cooling fan discharge air flow to be directed continually to the thermal clutch and away from the compressor which minimizes hardware changes utilized to implement such control technique.

In various other embodiments, the aspects of the systems and methods previously described may also be employed individually or in combination to diagnose the condition of a compressor. In one embodiment, a method for diagnosing a compressor includes operating a compressor in an unloaded condition by cycling the pistons within their respective cylinders, monitoring at least the reservoir pressure and the crankcase pressure, and determining a condition of the compressor based on an analysis of both the monitored reservoir pressure and crankcase pressure. In another embodiment, a method for diagnosing a compressor includes operating a multi-stage compressor to charge a reservoir with compressed air, monitoring at least a crankcase pressure and an intermediate stage pressure, and determining a condition of the compressor based on an analysis of both the monitored crankcase pressure and the monitored intermediate stage pressure. In yet another embodiment, a method for diagnosing a compressor includes monitoring signals from at least two of a primary reservoir pressure sensor, an intermediate reservoir pressure sensor, a crankcase pressure sensor, and a crankshaft position sensor, and correlating the monitored signals to identify a failure condition of the compressor. In yet another embodiment, a method of diagnosing a compressor includes actuating an unloader valve, monitoring at least a reservoir pressure sensor and a crankshaft position sensor, and identifying a leak condition of a valve disposed between a cylinder and a reservoir of a compressor. By way of example and not limitation, the subject disclosure can be utilized alone or in combination with a system and/or method disclosed in U.S. Provisional Application Serial No. 61/636,192, filed Apr. 20, 2012, and entitled “SYSTEM AND METHOD FOR A COMPRESSOR” in which the entirety of the aforementioned application is incorporated herein by reference.

The methods and systems disclosed herein may be applied to a reciprocating compressor having one or more compressor stages, such as the compressor illustrated in FIG. 2. In other embodiments, the methods and systems may be applied to other types of compressors. For example, the compressor may be a diaphragm or membrane compressor in which the compression is produced by movement of a flexible membrane. The compressor may also be a hermetically sealed or semi-hermetically sealed compressor. In addition, the compressor types may include centrifugal compressors, diagonal or mixed flow compressors, axial flow compressors, rotary screw compressors, rotary vane compressors, and scroll compressors, among others.

The methods presently disclosed may also include generating a signal corresponding to the failure condition and alerting an operator or other personnel so that remedial action may be taken. Each of these systems and methods described above may also be implemented on a vehicle system such as the rail vehicle 106 described above. In still yet other embodiments, a test kit is provided that includes a controller having a memory and a processor configured to perform the methods described above.

In each of the embodiments presently disclosed, component fault data may be recorded. In one embodiment, component fault data may be stored in a database including historical compressor data. For example, the database may be stored in memory 134 of controller 130. As another example, the database may be stored at a site remote from rail vehicle 106. For example, historical compressor data may be encapsulated in a message and transmitted with communications system 144. In this manner, a command center may monitor the health of the compressor in real-time. For example, the command center may perform steps to diagnose the condition of the compressor using the compressor data transmitted with communications system 144. For example, the command center may receive compressor data including cylinder pressure data from rail vehicle 106, reservoir pressure, intermediate stage pressure, crankcase pressure, displacement of one or more pistons, and/or movement of the crankshaft to diagnose potential degradation of the compressor. Further, the command center may schedule maintenance and deploy healthy locomotives and maintenance crews in a manner to optimize capital investment. Historical compressor data may be further used to evaluate the health of the compressor before and after compressor service, compressor modifications, and compressor component change-outs.

If a leak or other fault condition exists, further diagnostics and response may be performed. For example, a potential faulty valve condition can be reported to notify appropriate personnel. In an embodiment, reporting is initiated with a signal output to indicate that a fault condition exists. The report is presented via display 140 or a message transmitted with communications system 144, as examples. Once notified, the operator may adjust operation of rail vehicle 106 to reduce the potential of further degradation of the compressor.

In one embodiment, a message indicating a potential fault is transmitted with communications system 144 to a command center. Further, the severity of the potential fault may be reported. For example, diagnosing a fault based on the above described methods may allow a fault to be detected earlier than when the fault is diagnosed with previously available means. In some applications, the compressor is permitted to continue operating when a potential fault is diagnosed in the early stages of degradation. In other applications, the compressor is stopped or maintenance may be promptly scheduled, such as when the potential fault is diagnosed as severe. In this manner the cost of secondary damage to the compressor can be avoided by early and accurate detection.

The severity of the potential fault may be determined based upon an analysis of one or more parameters from one or more diagnostic methods. For example, it may be more desirable to switch off the compressor than to have a degraded cylinder fail in a manner that may cause additional damage to the compressor. In one embodiment, a threshold value or one or more monitored parameters may be determined that indicates continued operation of the compressor is undesirable because the potential fault is severe. As one example, the potential fault may be judged as severe if the leakage of an exhaust valve exceeds a predetermined threshold.

In some embodiments, a request to schedule service is sent, such as by a message sent via communications system 144. Further, by sending the potential fault condition and the severity of the potential fault, down-time of rail vehicle 106 may be reduced. For example, service may be deferred on rail vehicle 106 when the potential fault is of low severity. Down-time may be further reduced by derating power of the compressor, such as by adjusting a compressor operating parameter based on the diagnosed condition.

In yet other embodiments, backup or redundant systems may be available. In an example, backup systems can be evaluated to determine if adequate substitute resources exist to replace the compromised compressor. In some instances, a pre-ordered list of backup systems is used to prioritize the use of backup systems, such as other compressors configured to supply compressed air to pneumatic devices on a plurality of rail vehicles. Various backup systems may be employed including stopping the faulty compressor and receiving charged air from another source. In one example, the other source is a compressor that is disposed on an adjacent locomotive engine. In another example, the other source is a redundant compressor on the same locomotive that is used for this purpose. The backup procedure can be designed to minimize negative system-wide consequences to operation of the locomotive. This is useful for mission critical systems.

The aforementioned systems, components, (e.g., controller, detection component, among others), and the like have been described with respect to interaction between several components and/or elements. Such devices and elements can include those elements or sub-elements specified therein, some of the specified elements or sub-elements, and/or additional elements. Further yet, one or more elements and/or sub-elements may be combined into a single component to provide aggregate functionality. The elements may also interact with one or more other elements not specifically described herein.

In view of the exemplary devices and elements described supra, methodologies that may be implemented in accordance with the disclosed subject matter are described with reference to the flow chart of FIG. 19. The methodologies are shown and described as a series of blocks, the claimed subject matter is not limited by the order of the blocks, as some blocks may occur in different orders and/or concurrently with other blocks from what is depicted and described herein. Moreover, not all illustrated blocks may be required to implement the methods described hereinafter. The methodologies can be implemented by a component or a portion of a component that includes at least a processor, a memory, and an instruction stored on the memory for the processor to execute.

FIG. 19 illustrates a flow chart of a method 1900 for removing fluid from an aftercooler while maintaining pressure in a reservoir of a compressor. At reference numeral 1902, a temperature of a high pressure air that is delivered to a reservoir in the compressor can be reduced. In an embodiment, the temperature can be reduced by an aftercooler. At reference numeral 1904, air pressure within an aftercooler of the compressor can be isolated from air pressure within at least one of a high pressure air line or the reservoir. In an embodiment, the air pressure can be isolated with a check valve between the reservoir and the aftercooler. At reference numeral 1906, a portion of fluid can be removed from the aftercooler while maintaining air pressure in at least one of the high pressure air line or the reservoir.

In an embodiment, a system is provided that includes a filter that is external to the compressor that filters oil used with an engine, wherein the filter is coupled to an external surface of the compressor through a manifold. In the embodiment, the manifold can include a vent pin that enables oil to flow from the filter to the engine. In such embodiment, the vent pin can be configured to restrict a flow of oil from the filter to the engine via an oil vent and to enable oil flow from the filter to the engine via an oil vent. In the embodiment, the manifold can further include a pre-filter port that is configured to be utilized with an oil pump.

In an embodiment, the system can include an aftercooler coupled to o a high pressure cylinder of the compressor with a single exhaust pipe. In an embodiment, the system can include an intercooler coupled at least two low pressure cylinders of the compressor and a high pressure cylinder of the compressor. In an embodiment, the system can include an actuation line connecting at least one unloader valve of at least one low pressure cylinder of the compressor to at least one unloader valve of at least one high pressure cylinder of the compressor; a drain line connecting a drain valve of an intercooler of the compressor to the drain valve of the aftercooler of the compressor; and a discharge line that is coupled to at least one of the actuation line or the drain line that flows to the atmosphere for release thereto. In the embodiment, a controller can be configured to actuate the at least one unloader valve of the at least one low pressure cylinder, the at least one unloader valve of the at least one high pressure cylinder, the drain valve of the aftercooler, the drain valve of the intercooler, and the drain valve of the aftercooler at substantially the same time. In the embodiment of the system, the actuation can open each valve to the discharge line for flow to the atmosphere. In the embodiment of the system, the controller can be configured to actuate the check valve and the drain valve when the compressor is in an unloaded condition.

In the embodiment, the controller can be further to actuate at least one of the check valve or the drain valve prior to starting of the compressor. In the embodiment, the controller further configured to determine a high pressure cylinder discharge valve leak with an exhaust port based upon a flow from at least one of the check valve or the drain valve to the atmosphere. In an embodiment, a propulsion system can be provided with the system and can include a thermal clutch that engages a crankshaft to activate a fan for the compressor, wherein the thermal clutch engages the crankshaft based upon a temperature of an air flow discharged from the compressor.

In an embodiment, a method is provided that includes a step of removing the portion of fluid from the after cooler prior to starting a compressor to reduce air pressure resisting a high pressure cylinder head. In an embodiment, a method is provided that includes the steps of measuring a flow of the portion of fluid from the aftercooler; and identifying a high pressure cylinder discharge valve leak with an exhaust port based upon the measured flow. In an embodiment, a method is provide that includes the steps of engaging a thermal clutch with a crankshaft of the compressor based upon a temperature of an air flow discharged from the compressor; and activating a fan based upon the engagement of the thermal clutch. In an embodiment, a method is provided that includes the steps of filtering a portion of oil with an external oil filter for use with an engine of the compressor; flowing air from at least one unloader valve of a first low pressure cylinder to a drain valve coupled to at least one of the aftercooler or an intercooler of the compressor; flowing air from at least one unloader valve of a second low pressure cylinder to the drain valve; flowing air from at least one unloader valve of a first high pressure cylinder to the drain valve; or flowing air or the portion of fluid through the drain valve of the aftercooler to the atmosphere.

As used herein, the terms “high pressure” and “low pressure” are relative to one another, that is, a high pressure is higher than a low pressure, and a low pressure is lower than a high pressure. In an air compressor, low pressure may refer to a pressure that is higher than atmospheric pressure, but that is lower than another, higher pressure in the compressor. For example, air at atmospheric pressure may be compressed to a first, low pressure (which is still higher than atmospheric pressure), and further compressed, from the first, low pressure, to a second, high pressure that is higher than the low pressure. An example of a high pressure in a rail vehicle context is 140 psi (965 kPa).

In an embodiment, a system is provided that includes at least one of the following: means for delivering air under pressure to a reservoir (e.g., compressor, air line, high pressure air line 286, high pressure air line 288, among others); means for changing a temperature of the air that is delivered to the reservoir (e.g., aftercooler 270); means for isolating air pressure within the temperature changing means from air pressure within the reservoir (e.g., check valve 290); and means for removing a portion of fluid from the temperature changing means while maintaining air pressure in the reservoir (e.g., drain valve 292, drain line 294).

In the specification and claims, reference will be made to a number of terms that have the following meanings. The singular forms “a”, “an” and “the” include plural referents unless the context clearly dictates otherwise. Approximating language, as used herein throughout the specification and claims, may be applied to modify a quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term such as “about” is not to be limited to the precise value specified. In some instances, the approximating language may correspond to the precision of an instrument for measuring the value. Moreover, unless specifically stated otherwise, a use of the terms “first,” “second,” etc., do not denote an order or importance, but rather the terms “first,” “second,” etc., are used to distinguish one element from another.

As used herein, the terms “may” and “may be” indicate a possibility of an occurrence within a set of circumstances; a possession of a specified property, characteristic or function; and/or qualify another verb by expressing one or more of an ability, capability, or possibility associated with the qualified verb. Accordingly, usage of “may” and “may be” indicates that a modified term is apparently appropriate, capable, or suitable for an indicated capacity, function, or usage, while taking into account that in some circumstances the modified term may sometimes not be appropriate, capable, or suitable. For example, in some circumstances an event or capacity can be expected, while in other circumstances the event or capacity cannot occur—this distinction is captured by the terms “may” and “may be.”

This written description uses examples to disclose the invention, including the best mode, and also to enable one of ordinary skill in the art to practice the invention, including making and using a devices or systems and performing incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to one of ordinary skill in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differentiate from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims. 

What is claimed is:
 1. A system comprising: a compressor operatively connectable to an engine, wherein the compressor includes a reservoir configured to store compressed air, an aftercooler that is configured to change a temperature of air that is delivered to the reservoir via an air line, and a first drain valve coupled to the aftercooler; a check valve in line between the aftercooler and at least one of the air line or the reservoir, wherein the check valve is configured to isolate air pressure within the aftercooler and air pressure within the at least one of the air line or the reservoir; and a controller that is configured to: actuate the check valve to isolate air pressure within the aftercooler and air pressure within the at least one of the air line or the reservoir; and actuate the first drain valve coupled to the aftercooler to enable removal of fluid accumulated within the aftercooler.
 2. The system of claim 1, further comprising a filter that is external to the compressor that filters oil used with the engine, wherein the filter is coupled to an external surface of the compressor through a manifold.
 3. The system of claim 2, wherein the manifold further includes a vent pin that enables oil to flow from the filter to the engine.
 4. The system of claim 3, wherein: the vent pin, in a first mode of operation, is configured to restrict a flow of oil from the filter to the engine via an oil vent; and the vent pin, in a second mode of operation, is configured to enable the flow of oil from the filter to the engine via the oil vent.
 5. The system of claim 2, wherein the manifold further includes a pre-filter port that is configured to be utilized with an external oil pump application that access a portion of oil prior to entering the filter.
 6. The system of claim 1, wherein the aftercooler is coupled to a high pressure cylinder of the compressor with a single exhaust pipe.
 7. The system of claim 1, further comprising an intercooler coupled to at least two low pressure cylinders of the compressor and a high pressure cylinder of the compressor.
 8. The system of claim 1, further comprising: an actuation line connecting at least one first unloader valve of at least one low pressure cylinder of the compressor to at least one second unloader valve of at least one high pressure cylinder of the compressor; a drain line connecting a second drain valve of an intercooler of the compressor to the first drain valve of the aftercooler of the compressor; and a discharge line that is coupled to at least one of the actuation line or the drain line, wherein the discharge line flows to the atmosphere for release thereto.
 9. The system of claim 8, wherein the controller is further configured to: actuate the at least one first unloader valve of the at least one low pressure cylinder, the at least one second unloader valve of the at least one high pressure cylinder, the first drain valve of the aftercooler, and the second drain valve of the intercooler at substantially the same time.
 10. The system of claim 9, wherein the actuation opens each valve to the discharge line for flow to the atmosphere.
 11. The system of claim 9, wherein the controller is further configured to actuate the check valve and the first drain valve when the compressor is in an unloaded condition.
 12. The system of claim 9, wherein the controller is further configured to actuate at least one of the check valve or the first drain valve prior to starting of the compressor.
 13. The system of claim 9, wherein the controller is further configured to determine a cylinder discharge valve leak based upon a flow from at least one of the check valve, the first drain valve, or the second drain valve to the atmosphere.
 14. A propulsion system that includes the system of claim 1, and further comprising: a crankshaft; and a thermal clutch configured to engage the crankshaft to activate a fan for the compressor, wherein the thermal clutch is configured to engage the crankshaft based upon a temperature of an air flow discharged from the compressor.
 15. A method for a compressor, comprising: reducing a temperature of air that is delivered to a reservoir in the compressor; isolating air pressure within an aftercooler of the compressor from air pressure within at least one of an air line or the reservoir; and removing a portion of fluid from the aftercooler while maintaining air pressure in at least one of the air line or the reservoir.
 16. The method of claim 15, further comprising removing the portion of fluid from the aftercooler prior to starting the compressor to reduce air pressure resisting a cylinder head.
 17. The method of claim 15, further comprising: measuring a flow of the portion of fluid from the aftercooler; and identifying a cylinder discharge valve leak based upon the measured flow.
 18. The method of claim 15, further comprising: engaging a thermal clutch with a crankshaft of the compressor based upon a temperature of an air flow discharged from the compressor; and activating a fan based upon the engagement of the thermal clutch.
 19. The method of claim 15, further comprising: filtering a portion of oil with an external oil filter for use with an engine of the compressor; flowing air from at least one first unloader valve of a first low pressure cylinder to a drain valve coupled to at least one of the aftercooler or an intercooler of the compressor; flowing air from at least one second unloader valve of a second low pressure cylinder to the drain valve; flowing air from at least one third unloader valve of a first high pressure cylinder to the drain valve; and flowing air or the portion of fluid through the drain valve of the aftercooler to the atmosphere.
 20. A system for a compressor, comprising: means for delivering air under pressure to a reservoir; means for changing a temperature of the air that is delivered to the reservoir; means for isolating air pressure within the temperature changing means from air pressure within the reservoir; and means for removing a portion of fluid from the temperature changing means while maintaining air pressure in the reservoir. 